It is known that liquid dentifrice outperforms traditional viscous paste dentifrice in plaque removal because of liquid format that can easily penetrate into narrow spaces between teeth. In comparisons, paste dentifrices are too thick to penetrate these tiny spaces even with fine bristle. Therefore, the most effective method of teeth cleaning and plaque removal is a combination of applying and containing liquid dentifrice with bristles on tooth surfaces and in spaces between teeth while brushing. Furthermore, for better flow control, it is preferable to have incremental dispensing of liquid dentifrice without interrupting the continuous brushing motion.
For accomplishing brushing with liquid dentifrice, there are many features to be provided in a toothbrush for achieving the most effective and efficient brushing. A pump toothbrush must enable repeated pumping actions conveniently with one hand for dispensing incrementally without interrupting the brushing motion. The toothbrush should ensure full efficiency in dispensing expected amount of dentifrice at each pumping action that does not induce backflow and voids in the brush head. Furthermore, since paste dentifrices are being used by consumers, such a manual or electrical pump toothbrush is desirable to dispense any liquid and paste dentifrices while satisfying the above incremental dispensing and no backflow requirements.
(1) Field of the Invention
The present invention relates to a pump toothbrush using an elastic compressible button for repeated pumping during brushing and a piston-cartridge for the packing of liquid or paste dentifrice for reliable pumping. In particular it relates to means of delivering liquid dentifrice directly on teeth surfaces for maximum cleaning efficiency as well as a means of self-closing spout opening for preventing backflow and drying of dentifrice material in the brush head.
(2) Description of the Prior Art
There have been many patents in the prior art of dentifrice dispensing toothbrush. U.S. Pat. No. 5,909,977 by Kuo provides a dentifrice dispensing toothbrush for dispensing paste dentifrice with a paste or piston cartridge. A piston cartridge uses a piston for packing the dentifrice material for reliable pumping. However, the toothbrush does not provide positive means of preventing backflow and voids in the brush head in case of using liquid dentifrice. Due to low viscosity a liquid dentifrice material in the brush head can be freely sucked back into the pumping chamber as the elastic compressible button is released from a depressed position to its free-state position. The back flow causes voids in the flow channel of the brush head that leads to poor pumping efficiency as less amount of dentifrice being dispensed at each pumping action.
For dispensing liquid dentifrice, U.S. Pat. No. 6,241,412 by Spies et al. uses a pump assembly having an inlet port attached with an inlet needle for sucking liquid dentifrice stored in a cartridge. The concept is only for dispensing liquid dentifrice, pre-excluding the use of paste dentifrice as the inlet needle cannot suck viscous dentifrice material stored in the cartridge.
For dispensing dentifrice, U.S. Pat. No. 6,808,331 by Hall et al. describes a pump element located in the brush head portion of the toothbrush using the action of the moving brush head to move fluid from the on-board fluid reservoir to the bristles on the brush head. As a disadvantage, the fluid-dispensing system is not independent of the movement of the brush head. As a result, the dentifrice material is continuously dispensed while the brush head is being driven. In the powered toothbrush product with the trade name Intelliclean System of Sonicare and Crest manufactured by Philips and Procter & Gamble, specially formulated toothpaste is dispensed to the vibrating brush head for liquefying the toothpaste with high speed bristle motion to reach to hard-to-reach areas between teeth. The system requires special formulation of dentifrice material for transforming the dentifrice material into liquid form by spinning motion and it has a disadvantage that its dentifrice cartridge is not refillable by a user. It is preferable that liquid dentifrice of desirable viscosity can be directly dispensed for brushing without employing a complicated spinning mechanism and that a refillable cartridge be used for refilling by user for cost savings.
Furthermore, a dentifrice dispensing toothbrush is required to prevent drying of dentifrice material. For sealing the spout opening in the brush head, the U.S. Pat. No. 6,599,048 by Kuo uses a plug having a sealing rod shielded by an annular wall for engaging the spout wall of the opening in the brush head. The use of a plug is an extra step for sealing the spout opening, therefore, inconvenient for an user. In U.S. Pat. No. 5,746,532 by Megill, et al. a brush head is equipped with three slit valves. However, the closing of the valve elements requires an extra manual step of turning an actuator knob for creating a vacuum to withdraw toothpaste inward in the valve region. Since the valve closing is not automatic, neglecting the manual closing step may result in drying of the toothpaste. Therefore, it is desirable to have a self-closing spout that can automatically seal the dispensing opening after a pumping action.
(3) Objects of the Invention
It is an object of the present invention to provide a pump toothbrush with a pump head having an elastic compressible button for the convenience of repeated pumping during brushing with one hand and using a common pump head and a common cartridge for dispensing any liquid and paste dentifrices. It is also an objective to provide a self-closing spout opening for preventing backflow and drying of dentifrice material in the brush head. It is a further objective to meet these requirements for both manual and electrical pump toothbrushes.